The Motion Picture Expert Group (MPEG) video specifications (i.e., ISO/IEC standard 11172, ISO/IEC standard 13818, etc.) are very complicated industry standards for compressing, transmitting, and decompressing digital video signals for a variety of situations. Due to the complexity of the MPEG standard, devices that properly process MPEG compliant bit streams are at least as complex as the MPEG specification.
Because of the complexity of the devices that implement MPEG processing, most MPEG video decoders execute many features of the MPEG process without intervention of a video decoder system central processing unit (CPU). Most CPUs would be overwhelmed by the quantity of the processing that is performed on a standard MPEG bit stream. However, some MPEG video decoders perform so much of the MPEG video processing that information the system CPU might require for the system to function properly is not provided by the decoder. For example, when errors are detected in the picture data some MPEG decoders will skip (i.e., fail to decode) the MPEG video frames without notifying the system CPU of the skip. Frame skips can cause a problem when the skipped frames are displayed. The CPU will not be notified that the MPEG decoder has not decoded these frames and will attempt to display the un-decoded frames as normal (i.e., decoded) frames. Invalid and/or incoherent video images can be displayed.
It would be desirable to have a video decoder that (i) is compliant with MPEG standards, (ii) detects when a video frame has been skipped, (iii) provides the system CPU notification that the respective frame was skipped, and/or (iv) reduces and/or eliminates the display of un-decoded video frames due to frame skips.